Charles Hightower on sat 3 nov 07
I was reading on the digitalfire website that an addition of zirconium
silicate can greatly increase the whiteness of a clay body. I don't care a
great deal about translucency. Has anyone tryed this and if so, what
percent addition? I've certainly heard of more expensive additions such as
cobalt and rare earths. It will be for a throwing body I'm working on.
Leigh Whitaker on sat 3 nov 07
In a message dated 11/3/2007 2:55:26 P.M. Eastern Standard Time,
hightowerceramics@YAHOO.COM writes:
I was reading on the digitalfire website that an addition of zirconium
silicate can greatly increase the whiteness of a clay body. I don't care a
great deal about translucency. Has anyone tryed this and if so, what
percent addition? I've certainly heard of more expensive additions such as
cobalt and rare earths. It will be for a throwing body I'm working on.
I can't tell you anything about in a throwing clay, but I've made some slip
from Standard #153 and added superpax. It worked fine and whitened it quite
a bit. I added oh... about 2.5-5% of the dry weight.
Leigh
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Charles Hightower on sat 3 nov 07
Was this for slip casting? I was thinking that a coat of body slip with the
superpax applied after throwing would save on cost. I'm going for cold
white, but don't wish to give up my plastic ingredients. Copper red glaze
is going over that. Thanks for the percentage.
Leigh Whitaker on sun 4 nov 07
In a message dated 11/3/2007 9:27:37 P.M. Eastern Standard Time,
hightowerceramics@YAHOO.COM writes:
Was this for slip casting? I was thinking that a coat of body slip with the
superpax applied after throwing would save on cost. I'm going for cold
white, but don't wish to give up my plastic ingredients. Copper red glaze
is going over that. Thanks for the percentage.
No, I am applying colored slips on top of pots and then carving them away to
make a sort of marbled pattern. Covering with a white slip would certainly
save you on cost. I'm not sure how white you can get it with superpax though.
My percentages probably didn't get it to cold white, but I was just looking
for a contrast to the original clay color, so it was okay for what I was
doing.she didn't
There are some decent white throwing clays though (as I'm sure you know). I
don't know what temp you are going to, but I just recently started playing
with Standard #182 which is a fairly plastic and close to white. Standard
also makes a cone 6 porcelain that is very white. I've played with it a little
and it's not too bad to throw. (Standard is just the supplier for my local
pottery shop, so those are the clays I'm familiar with). So if the
experiments with superpax don't work out, you might give a white stoneware a try.
Sorry if this was disjointed, my 4 year old is serving me pretend cupcakes
and cookies so I am a little distracted!
Leigh
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Charles Hightower on sun 4 nov 07
I'm firing cone 6 reduction. My body is my own porcelain and it contains
small percentages of both OM4 ball clay and bentonite. Since I will be
doing the slip method I may even add .01% cobalt carb on top of the 5%
superpax (now zircopax plus I believe) to give me that cool "unreal" white
I'm after to contrast the rich copper red glaze. Thanks again.
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